Table 2.

Oligomeric state of purified proteins

Protein	Original sequence	Lys in N-term. β-strand	Lys in C-term. β-strand	Double mutant
4-6	Oligomer	Monomer & olig.	Oligomer	Monomer
17-6	Oligomer	Monomer	Oligomer	Monomer
45-8	Oligomer	Monomer & olig.	Oligomer	Monomer

Oligomeric state was determined by SEC. Proteins eluting in the void volume of the column were designated as high order oligomers. Those eluting at volumes similar to that of plastocyanin were designated as monomers. (Poplar plastocyanin is a 100-residue β-sheet protein.) Examples of chromatograms are shown in Fig. 2.